基于模式项散射的吸波结构

Novel absorbing structure based on antenna mode scattering

天线雷达散射截面(RCS)的缩减是隐身平台实现低散射特性的关键。吸波结构是缩减目标RCS的重要技术手段,而又难以避免对天线辐射性能产生恶化影响。针对微带天线提出了基于模式项散射的吸波结构设计方法,利用吸波结构模式项散射与微带天线的结构项散射进行对消,达到天线带外雷达散射截面缩减的效果。通过仿真验证,在工作中心频率为10 GHz的微带天线2×2元阵加载该吸波结构,可在不影响天线阵列辐射性能的基础上,对天线阵列5 GHz的法向RCS带来8 dB缩减效果。实测结果表明,在某Ka频段天线阵列加载该吸波结构,对天线阵列X频段法向RCS有6 dB缩减效果。

Reduction of antenna radar cross section(RCS)is critical to realize low scattering characteristics of stealth platform.Absorbing structure is an important technical means to reduce the RCS of target,however,it is difficult to avoid deteriorating the antenna radiation performance.A method of novel absorbing structure design was proposed for microstrip antenna to cancel antenna mode scattering of the absorbing structure and structural mode scattering of the microstrip antenna,which reduced the out-of-band RCS of the microstrip antenna.Simulation shows that loading the absorbing structure in 2×2 array microstrip antenna at central working frequency of 10 GHz can bring 8 dB reduction on the normal RCS at 5 GHz without affecting the radiation performance of the antenna array.Experimental results show that loading the absorbing structure on a Ka band antenna array can reduce the X band normal RCS by 6 dB.